【Objective】Purple soil is a soil type unique to China, characterized by rapid weathering of the parent material, low permeability, and poor erosion resistance. A large number of slope conversions have been adopted to combat soil erosion, but the synergistic effect of this measure with crop types on the local organic carbon pools of sloping arable land and their composition is not clear. 【Method】In this study, Corn Slope, Corn Terracing, Citrus Slope, Citrus Terracing, Corn-Citrus Terracing in the East River sub-basin in Chongqing were selected as the research objects. Biomarker methods were used to compare the differences in soil microorganisms and organic carbon of plant origin from different types of sloping arable land and to reveal the effects of slope-to-staircase measures on soil organic carbon pools and their compositions.【Results】The results showed that: 1) The contents of SOC, POC, and MAOC in different types of sloping arable land was significantly decreased with the implementation of slope reclamation measures; 2) Slope reclamation significantly decreased the total lignin phenol content in maize sample plots compared to the significant decrease in the degree of oxidation of lignin phenol in citrus sample plots; 3) The main source of microbial organic carbon in all sample plots was fungal residue, which accounted for 74.50%~98.88%, and the slope conversion measures decreased the fungal content in the soil under the monocrop planting mode. 【Conclusion】Although slope conversion measures helped to reduce soil erosion, they had a complex impact on the soil organic carbon pool and its composition in sloping arable land in the purple soil zone. This provides a scientific basis for optimising agricultural management practices and achieving sustainable land use in the purple soil zone.